JP2018104751A - Method of producing composite particle dispersion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a composite particle dispersion containing a metal particle adhering to the surface of a resin particle.SOLUTION: The method of producing a composite particle dispersion includes at least the steps of: arranging a second liquid phase obtained by dissolving a reducer, dissolving or dispersing a dispersant, and dispersing a resin particle, and a phase of a low dielectric constant liquid so as to stack in a 2 phase separation manner; arranging a spraying opening of a nozzle in the phase of the low dielectric constant liquid, or arranging the spraying opening of the nozzle so as to face a liquid surface of the phase of the low dielectric constant liquid at a position separated to a phase side of the low dielectric constant liquid from the two phases; arranging an electrode in a phase of the second liquid; applying a potential difference between the nozzle and the electrode to charge; and spraying electrostatically liquid droplets of a first liquid obtained by dissolving a metal salt to subject the metal salt reaching the phase of the second liquid through the low dielectric constant liquid to reductive reaction with the reducer so that the composite particle dispersion in which composite particles attached with generated metal particles on the resin particle surface are dispersed in the second liquid is obtained.SELECTED DRAWING: None

Description

  The present invention relates to a method for easily producing composite particles having conductivity and catalytic action.

  Conventionally, as the conductive paste, a mixture of a conductive inorganic filler and an organic polymer as a binder has been used. In order to improve the conductivity of the conductive paste, it is necessary to increase the mixing ratio of the conductive inorganic filler, but there are problems in terms of cost and mechanical strength reduction. In order to cope with the problem, core-shell particles have been proposed in which an organic material is a core and an inorganic conductive material is a shell.

As a method of coating metal particles and metal films on the surface using organic as a core material, a method using electroless plating (Patent Document 1) and a method of attaching metal nanocolloids such as thiol to an organic material (Patent Document 2) Is used.
In the method of forming a metal film by plating method, a step of pre-treatment such as etching is performed on the organic material to enhance plating non-stickiness, and a catalyst is applied to activate plating to grow the plating film. It was necessary to generate a large amount of waste water for performing complicated steps such as a step to be performed and cleaning for each step.
For the method of attaching metal nanocolloids, a method has been proposed in which a thiol compound is imparted to the surface of an organic material to give affinity, and then the metal nanocolloid is slowly attached to the surface in several days at room temperature. Has been.

As a mechanical operation method, a method of combining solid particles by surface welding by applying strong mechanical energy to a plurality of different material particles has been proposed (Patent Document 3).
However, in any method, there are problems in cost and environment, such as pretreatment such as modification of the organic material as a core, increase in production time, and application of physical energy. Recently, a method for producing fine metal particles using electrostatic spraying has been proposed (Patent Document 4).

JP 2004-14409 A JP 2006-233255 A JP 2010-144152 A International Publication No. 2016/031695

  The present invention has been made in view of the above problems, and is a method for producing a dispersion of composite particles comprising resin particles and metal particles adhering to the surfaces of the resin particles. An object of the present invention is to provide a method for producing composite particles that can be easily adapted to a wide range of applications without complicated preparation for compound liquids and resin particles.

  In order to achieve the above object, according to the present invention, a reducing agent is dissolved, a dispersing agent is dissolved or dispersed, and a second liquid phase in which resin particles are dispersed and a low dielectric constant liquid phase are divided into two. The nozzles are arranged so as to be phase-separated, and the nozzle spray nozzle is arranged in the phase of the low dielectric constant liquid, or the low dielectric constant is separated from the two phases to the phase side of the low dielectric constant liquid. In the state where the liquid is directed toward the liquid surface of the liquid phase and the electrode is disposed in the phase of the second liquid, the metal salt is charged by applying a potential difference between the nozzle and the electrode. The dissolved liquid droplets of the first liquid are electrostatically sprayed from the spray nozzle of the nozzle, and the metal salt that has reached the second liquid phase through the low dielectric constant liquid phase is reduced. The composite particles in which the generated metal particles are attached to the surface of the resin particles are reduced by a reducing reaction with the agent. Comprising at least the step of obtaining the composite particle dispersion was dispersed in 2 liquid, method for producing a composite particle dispersion is provided.

  According to the production method of the present invention, the conductive metal particles are coated on the resin particles as the core or the metal particles having a catalytic action without applying a special pretreatment to the metal compound liquid and resin particles as raw materials. It can be dotted.

It is an example of the apparatus used when obtaining a metal particle dispersion using electrostatic spraying.

The composite particles include resin particles and metal particles attached to the surfaces of the resin particles.
The resin particle is, for example, a polymer such as a thermosetting polymer or a thermoplastic polymer. Examples of the thermosetting polymer include epoxy resins, curable polyamides, phenol resins, melamine resins, polyurethanes, and silicones. Examples of the thermoplastic polymer include polyester, polyurethane, polyamide, polyimide, acrylic resin, polycarbonate, and polystyrene. The glass transition point (Tg) of these resins is preferably -50 ° C to 100 ° C. These resins can be used alone or in combination of two or more. As the resin particles, polyurethane, polyester, acrylic resin, and polystyrene can be preferably used.
Since the resin particles are used in a state dispersed in the second liquid, the average particle size of the resin particles is preferably 10 nm to 50 μm, more preferably 50 nm to 1 μm. The average particle diameter of the resin can be measured by a dynamic light scattering method (DLS). The concentration of the dispersion liquid in which the resin particles are dispersed in the second liquid is preferably 0.01 to 40% by mass from the viewpoint that the dispersibility of the resin particles is more excellent.

Examples of the metal species of the metal particles include a conductive metal having conductivity and a metal having a catalytic action. As the conductive metal, silver, copper, tin, nickel, gold and the like are preferable from the viewpoint that the conductivity of the composite particle is more excellent, and as the metal having a catalytic action, from the viewpoint that the catalytic performance of the composite particle is more excellent. Platinum, gold, iron, palladium, zinc, cobalt, tungsten, indium, selenium and the like are preferable. The form of the metal particles may be one single form, or a mixed form or complex form of two or more metals.
The average particle diameter of the metal particles can be controlled by, for example, the size of the first liquid droplet in which the metal salt is dissolved, but the average particle diameter of the metal particles is preferably 1 to 100 nm, more preferably 5 to 50 nm. It is. The average particle diameter of the metal particles can be measured using a field emission scanning electron microscope (FE-SEM).

The composite particle is a composite particle in which metal particles are attached to the surface of the resin particle, and the resin particle is covered with the particle particle intermittently or discontinuously or the resin particle is a core and the metal particle is a shell layer. The aspect which the metal particle covers the surface of particle | grains continuously is included. In the point that the composite particles have conductivity, an embodiment in which the metal particles continuously cover the surface of the resin particles is preferable, and the thickness of the metal particle layer is preferably 10 to 50 nm. When the thickness of the metal particle layer is 10 nm or more, the conductivity of the composite particle is more excellent, and when it is 50 nm or less, the conductivity obtained with respect to the thickness of the metal particle layer (metal particle amount) is more excellent.
In terms of the composite particles having conductivity and catalytic function, the average particle size of the metal particles is preferably smaller than the average particle size of the resin particles. The ratio between the average particle diameter of the metal particles and the average particle diameter of the resin particles is preferably 1/100 to 1/1000, and more preferably 1/5 to 1/50, in terms of obtaining conductivity and catalytic function. The mass ratio between the metal particles and the resin particles varies depending on the specific gravity of the metal to be combined, but is, for example, 1 to 10/10. The mass ratio of the metal particles to the resin particles is controlled by, for example, the concentration of the metal salt dissolved in the first liquid, the amount of droplets sprayed from the nozzle opening, the concentration of the resin particles dispersed in the second liquid, etc. it can.

  The composite particle dispersion is arranged so that the reducing agent is dissolved, the dispersing agent is dissolved or dispersed, and the second liquid phase in which the resin particles are dispersed and the low dielectric constant liquid phase are separated into two phases. The spray port of the nozzle is arranged in the phase of the low dielectric constant liquid, or on the liquid surface of the phase of the low dielectric constant liquid at a position away from the two phases to the phase side of the low dielectric constant liquid. The first liquid in which the metal salt is dissolved while being charged by applying a potential difference between the nozzle and the electrode with the electrode disposed in the phase of the second liquid. The droplets are electrostatically sprayed from the nozzle nozzle, the metal particles react with the reducing agent in the second liquid phase, and the composite particles having the metal particles attached to the surface of the resin particles are formed. A method comprising at least a step of obtaining a composite particle dispersion dispersed in a second liquid More can be produced.

  A method for obtaining fine metal particles using electrostatic spraying is described in detail in Patent Document 4. The metal particle dispersion can be produced, for example, using the apparatus shown in FIG. The incompatible low dielectric constant liquid LL and the second liquid L2 are accommodated in the inside of the container 6 which may be sealed and may be opened upward. In FIG. 1, a phase composed of a low dielectric constant liquid LL (hereinafter also referred to as a “low dielectric constant liquid phase”) P1 is disposed on the upper portion of the container 6, and a phase composed of a second liquid L2 (hereinafter referred to as “second phase”). P2) (referred to as “liquid phase”) is disposed in the lower part of the container 6, and the low dielectric constant liquid phase P1 and the second liquid phase P2 overlap with each other with the interface as a boundary. As described in Patent Document 4, the specific gravity of the low dielectric constant liquid phase is set higher than the specific gravity of the second liquid phase, and the low dielectric constant liquid phase is set at the lower portion and the second liquid phase is set at the upper portion. It is also possible. The first liquid L1 is sprayed from a spray port 1a of an electrospray nozzle (hereinafter, also referred to as “nozzle”) 1 configured to be capable of electrostatic spraying the first liquid L1 in a droplet state. The electrode 4 disposed in the second liquid L2 with a space from the spray port 1a is opposed to the spray port 1a of the nozzle 1 with a distance of W1. The power source 5 is electrically connected to each of the nozzle 1 and the electrode 4 and is configured to provide a positive potential to the nozzle 1 and a negative potential to the electrode 4. In FIG. 1, the spray port 1a of the nozzle 1 is arranged in the low dielectric constant liquid phase P1 with a gap between the interface B and the distance W2, but the low dielectric constant liquid phase P1 is located above the low dielectric constant liquid phase P1. The liquid surface may be arranged at a distance W3 (not shown) from the liquid surface so as to face the liquid surface.

  The distance W1 between the spray port 1a of the nozzle 1 and the electrode 4 is preferably 1 cm or more, preferably 2 cm or more. The distance W2 between the spray port 1a of the nozzle 1 and the interface between the low dielectric constant liquid phase P1 and the second liquid phase P2 can be appropriately adjusted depending on the container capacity, potential difference, etc., but should be a value smaller than the distance W1. For example, 1 cm or more is preferable, and 2 cm or more is more preferable. For example, in the case of a beaker with a capacity of 10 L, the upper limit of the distance W2 can be set to 20 cm by adjusting the potential, and can be appropriately adjusted according to the container capacity, the potential difference, and the like.

  The sprayed droplets containing the metal salt move along the electric field gradient through the low dielectric constant liquid phase P1 to the second liquid phase P2, react with the reducing agent, and the reaction product is in the second liquid phase P2. And a dispersion of the reaction product is obtained in the second liquid phase P2. The second liquid phase P2 is separated from the low dielectric constant liquid phase P1, and the dispersion obtained in the second liquid phase P2 can be recovered.

  The first liquid is preferably water, ethanol, DMF, acetone, or a mixture of two or more of these. Particularly preferred is water, or an aqueous solution of water and a water-soluble solvent such as ethanol, DMF, or acetone.

Examples of the metal salt contained in the first liquid include chloroplatinic acid salts such as chloroplatinic acid, potassium chloroplatinate, and ammonium chloroplatinate, gold chloride such as chloroauric acid, sodium chloroaurate, and ammonium chloroaurate. Selenium such as acid salt, silver nitrate, copper sulfate, copper nitrate, tin chloride, iron chloride, nickel sulfate, palladium chloride, zinc chloride, cobalt acetate, sodium tungstate, indium nitrate, sodium selenate, potassium selenate, ammonium selenate Examples include acid salts.
The concentration of the metal salt in the first liquid is preferably 0.001 to 4 mol / L.

  The second liquid is preferably an aqueous solution system or water-soluble that is compatible with the first liquid. Furthermore, the second liquid is preferably water, ethanol, DMF, acetone, or a mixture of two or more of these from the viewpoint of facilitating energization. Particularly preferred is water, or an aqueous solution of water and a water-soluble solvent such as ethanol, DMF, or acetone.

  The reducing agent contained in the second liquid is selected to be compatible with the metal species to be reduced. Examples of reducing agents include hydroxymethanesulfinic acid, thioglycolic acid, sulfurous acid and their salts, citric acid, ascorbic acid, sodium hydrosulfite, thiourea, dithiothreitol, hydrazines, formaldehydes, and boron hydrides. Can be used alone or in combination of two or more.

The hydrazines used as the reducing agent may be hydrazine, hydrazine hydrate, hydrazine salts, hydrazine substituent derivatives or salts thereof, and the like. Specific examples include hydrazine hydrate, hydrazine monohydrochloride, hydrazine dihydrochloride, hydrazine sulfate, hydrazine odorate, hydrazine carbonate, methyl hydrazine, phenyl hydrazine, tert-butyl hydrazine hydrochloride, carbohydrazide and the like.
Examples of formaldehydes used as the reducing agent include formaldehyde and paraformaldehyde, and it is preferable to use one or a combination of two or more.

Boron hydrides used as a reducing agent represent a reducing compound having a boron-hydrogen bond. Specifically, sodium borohydride, potassium borohydride, lithium borohydride, sodium cyanotrihydroborate, lithium Examples include triethylborohydride, tetrahydrofuran / borane complex, dimethylamine / borane complex, diphenylamine / borane complex, and pyridine / borane complex.
In particular, the reducing agent is preferably ascorbic acid or hydrazines.

  The amount of the reducing agent added can be appropriately adjusted according to the type of the reducing agent, the concentration of the metal salt, and the like. For example, the amount of the reducing agent added is preferably in the range of 1 to 50 times the chemical equivalent (stoichiometric amount, stoichiometry). If the addition amount of the reducing agent is less than the chemical equivalent, the reduction reaction to metal ions may not proceed sufficiently. On the other hand, the amount of the reducing agent added may exceed 50 times the chemical equivalent, but the cost increases.

The second liquid contains a dispersant.
Surfactant as a dispersant, gum arabic, polyvinyl alcohol, polyvinyl pyrrolidone, cellulose derivative, acrylic acid polymer and copolymer thereof, maleic anhydride copolymer, styrene maleic anhydride copolymer as polymeric dispersant Products, isobutylene maleic anhydride copolymer, polyacrylamide, and 2-acrylamido-2-methyl-propanesulfonic acid polymer and copolymers thereof. There is no restriction | limiting in particular as surfactant, Nonionic surfactant, anionic surfactant, cationic surfactant, amphoteric surfactant etc. are mentioned. As a dispersing agent, 1 type of these or the combination of 2 or more types may be sufficient. From the viewpoint that the composite particle dispersion can be further stabilized, nonionic surfactants and polymer dispersants are preferable. As the polymer dispersant, polyvinyl alcohol and polyvinyl pyrrolidone are preferable.

  Anionic surfactants include those having a sulfo group such as α-olefin sulfonate, alkylbenzene sulfonate, paraffin sulfonate, α-sulfo fatty acid salt, α-sulfo fatty acid alkyl ester salt, higher alcohol sulfate ester salt , Those having a sulfate group such as polyoxyethylene alkyl (or alkenyl) ether sulfate, and those having polyoxyethylene alkyl (or alkenyl) ether phosphate, and one or a combination of two or more It should be used.

  Examples of the cationic surfactant include monoalkyltrimethylammonium salts, dialkyldimethylammonium salts, monoalkylamine acetates, dialkylamine acetates, alkylimidazoline quaternary salts, and the like, by using one kind or a combination of two or more kinds. There should be. In addition, as for carbon number of all alkyl groups, it is preferable in it being 8-24.

  Examples of amphoteric surfactants include alkylbetaines, fatty acid amidopropylbetaines, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaines, alkyldiethylenetriaminoacetic acids, dialkyldiethylenetriaminoacetic acids, alkylamine oxides, and the like. One type or a combination of two or more types may be used.

Nonionic surfactants include fatty acid esters of alcohols or alkylene oxide adducts of alcohols, fatty acids esters of phenols or alkylene oxide adducts of phenols, phenols, or alkylene oxide adducts of alcohols having 8 to 24 carbon atoms. , Ethylene oxide and / or propylene oxide polymer (pluronic nonionic surfactant), alkylamine alkylene oxide adduct, fatty acid amide alkylene oxide adduct, alkanolamine fatty acid amide, etc. It is good to use 2 or more types of combinations.
Preferably, the nonionic surfactant is a fatty acid ester of an alcohol or an alkylene oxide adduct of alcohol, a fatty acid ester of a phenol or an alkylene oxide adduct of phenol, a phenol or an alkylene of an alcohol having 8 to 24 carbon atoms. An oxide adduct is mentioned, It is good to use 1 type or the combination of 2 or more types. More preferably, the nonionic surfactant is a fatty acid ester of an alcohol or an alkylene oxide adduct of alcohol.

  Phenols are those in which a hydroxy group is bonded to an aromatic ring. Examples of phenols include phenol, mono, di or tristyrenated phenol, alkylphenol, mono, di or tristyrenated alkylphenol. Phenols can preferably have 1 to 12 carbon atoms in the alkyl group and 1 to 3 bonds to the aromatic ring.

The alkylene oxide is preferably an alkylene oxide having 2 to 3 carbon atoms. In particular, the alkylene oxide is preferably ethylene oxide or propylene oxide from the viewpoint that the dispersibility of the resin particles or the resulting composite particles can be further improved.
As an example, the alcohol in the fatty acid ester of alcohol or an alkylene oxide adduct of alcohol may be an alcohol having 1 to 24 carbon atoms and 1 to 6 valences. From the viewpoint that the resin particle dispersion and the resulting composite particle dispersion can be further stabilized, these alcohols are preferably alcohols having 3 to 12 carbon atoms and 2 to 6 valences. Furthermore, these alcohols are more preferably having 3 to 6 carbon atoms.
Stabilization of the resin particle dispersion or composite particle dispersion means that aggregation of resin particles and composite particles is further suppressed.

  Examples of the alcohol include sorbitan, sugar alcohol, sugar and the like. Among these, examples of the sugar alcohol include glycerin, erythritol, threitol, arabitol, xylitol, pentaerythritol, ribitol, iditol, dulcitol, sorbitol, mannitol and the like. Examples of the sugar include monosaccharides such as glucose, erythrose, arabinose, mannose, galactose and fructose, and disaccharides such as sucrose and trehalose. From the viewpoint that the resin particle dispersion and the resulting composite particle dispersion can be further stabilized, the alcohol is preferably sorbitan, glycerin, pentaerythritol, sorbitol, or sucrose. Furthermore, the alcohol is preferably sorbitan, glycerin, or sorbitol.

  For example, the fatty acid may be a fatty acid having 8 to 22 carbon atoms. In particular, the fatty acid is preferably a fatty acid having 12 to 18 carbon atoms from the viewpoint that the resin particle dispersion and the resulting composite particle dispersion can be further stabilized. Such fatty acids may be dodecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, hexadecenoic acid, heptadecanoic acid, octadecanoic acid, octadecenoic acid, octadecanedienoic acid, octadecanetrienoic acid and the like. Furthermore, from the viewpoint that the resin particle dispersion and the resulting composite particle dispersion can be further stabilized, the average number of added moles of alkylene oxide is preferably 5 to 100 moles in ethylene oxide, and 0 moles in propylene oxide. It is preferable that it is 10 mol.

  The fatty acid ester of alcohol or an alkylene oxide adduct of alcohol may be an oil or fat derived from a natural product, a hydrogenated oil or a semi-cured oil thereof, or an alkylene oxide adduct thereof. The fats and oils may be castor oil, peanut oil, olive oil, rapeseed oil, palm oil, palm oil, palm kernel oil, beef tallow, sheep fat and the like. In particular, from the viewpoint that the resin particle dispersion and the resulting composite particle dispersion can be further stabilized, it is preferable that the fat is castor oil.

  The phenol in the alkylene oxide adduct of phenol is preferably tristyrenated phenol. Further, from the viewpoint that the resin particle dispersion and the resulting composite particle dispersion can be further stabilized, the average added mole number of alkylene oxide is preferably 5 to 40 mol in ethylene oxide, and 0 mol to 0 in propylene oxide. It is preferable that it is 10 mol. From the viewpoint that the resin particle dispersion and the resulting composite particle dispersion can be further stabilized, the alcohol in the alkylene oxide adduct of alcohol having 8 to 24 carbon atoms is an aliphatic alcohol having 12 to 22 carbon atoms. Preferably there is. Moreover, from the viewpoint that the resin particle dispersion and the resulting composite particle dispersion can be further stabilized, the number of added moles of alkylene oxide is preferably 1 to 30 moles in ethylene oxide, and 0 to 5 moles in propylene oxide. Preferably it is a mole.

  The concentration of the dispersant is preferably a concentration at which micelles are formed. The concentration of the solution or dispersion in which the dispersant is dissolved or dispersed in the second liquid is, for example, 0.1% by mass or more and 10%. It is good to set it as the range below mass%. Further, the concentration is more preferably in the range of 0.1% by mass or more and 5% by mass or less from the viewpoint that the composite particle dispersion can be further stabilized and can be handled more easily. At this time, the concentration of the dispersion liquid in which the resin particles are dispersed in the second liquid is preferably 0.01 to 40% by mass.

The low dielectric constant liquid is not compatible with the first and second liquids, and the relative dielectric constant of the low dielectric constant liquid is lower than that of the first and second liquids.
The low dielectric constant liquid is preferably a water-insoluble organic solvent. The relative dielectric constant of the low dielectric constant liquid is 25 or less, preferably 20 or less, more preferably 15 or less, further preferably 10 or less, and further preferably 5 or less. When the relative dielectric constant is 25 or less, the potential difference is more easily adjusted. Usable low dielectric constant liquids include normal paraffin hydrocarbons such as hexane, heptane, octane, nonane, decane and dodecane, isoparaffin hydrocarbons such as isooctane, isodecane and isododecane, cyclohexane, cyclooctane, cyclodecane and decalin. Hydrocarbon solvents such as cycloparaffin hydrocarbons, liquid paraffin and kerosene; aromatic solvents such as benzene, toluene and xylene; chlorine solvents such as chloroform and carbon tetrachloride; perfluorocarbon, perfluoropolyether, hydro Fluorine-based solvents such as fluoroethers; alcohol-based solvents such as 1-butanol (relative permittivity 17.51), 1-pentanol (relative permittivity 13.90), 1-octanol (relative permittivity 10.30); And of these May is a mixture of more kinds. As an example, isoparaffin is IP solvent 1016 manufactured by Idemitsu Kosan Co., Ltd., or IP Clean LX (registered trademark), Marcazole R manufactured by Maruzen Petrochemical Co., Ltd., Isopar H (registered trademark) manufactured by ExxonMobil, and Isopar E ( Registered trademark) or Isopar L (registered trademark).

In the present invention, by adjusting the potential difference between the nozzle and the electrode, the metal raw material concentration, the surfactant concentration, the reducing agent concentration, the low dielectric constant liquid and the chemical interaction between the metal raw material solution sprayed from the nozzle port, etc. It is possible to control the shell layer of the metal particles, which are reaction products that adhere to the surface of the resin particles that are the core, or to control the size of the composite particles that are the reaction products.
In particular, in order to form a dense metal layer, the average particle diameter of the droplets is preferably in the range of 0.1 μm or more and 100 μm or less. Furthermore, the average particle diameter is more preferably in the range of 1 μm or more and 10 μm or less.

The type of low dielectric constant liquid, the amount of droplets sprayed from the nozzle port (ie, the feed rate of the aqueous metal salt solution toward the aqueous phase), the type of reducing agent, the distance between the nozzle port spray port and electrode, the nozzle Adjust the distance between the spray port and the water phase, the potential difference between the nozzle and the electrode, etc., and control the size of the droplets, the size of the metal particles can be adjusted, and the density of the deposited metal particles can be controlled Can do.
For example, by increasing the ionic strength of the aqueous metal solution, the surface tension can be increased and the droplet size can be increased. By reducing the dielectric difference between the aqueous metal solution and the relative dielectric constant solvent, the size of the droplet can be increased. Thus, the size of the metal particles can be increased by increasing the size of the droplets. In addition, the size of the droplet can be reduced by increasing the potential difference between the nozzle and the electrode. By reducing the size of the droplets in this way, the size of the generated metal particles can be reduced.

  The potential on the nozzle side is preferably in the range of −30 kV to 30 kV, and the potential on the electrode side is also preferably in the range of −30 kV to 30 kV. The potential difference between the nozzle and the electrode may be adjusted so as to match the obtained reactivity and shell layer. For example, the potential difference between the nozzle and the electrode may be in the range of 0.3 kV to 30 kV in absolute value. Further, considering the stability of the reaction product, the potential difference between the nozzle and the electrode is preferably 2.5 kV or more in absolute value, and considering the safety and cost of the apparatus, the potential difference is absolutely The value is preferably 10 kV or less.

The spray amount of droplets from the nozzle may be selected so as to match the reaction amount. For example, from the viewpoint that the composite particle dispersion can be further stabilized, the spray amount is set to a range of 0.001 mL / min (min) to 2.0 mL / min. It may be adjusted, more preferably in the range of 0.05 to 1.0 mL / min.
For example, the conductive composite particles (conductive particles) are core-shell composite particles obtained by attaching the metal particles to the resin particles so as to form a metal layer (shell). From the viewpoint, when producing such particles, the resin is prepared so that the concentration of the dispersion obtained by dispersing the resin particles (average particle diameter of 10 nm to 50 μm) in the second liquid is 0.01 to 40% by mass. In the second liquid in which the particles are dispersed, a solution having a metal salt concentration of 0.001 to 4 mol / L is preferably 5 minutes or more at a liquid feed rate of 0.01 to 1 mL / min from the viewpoint of more excellent conductivity. Can be exemplified by the condition of electrostatic spraying for 10 minutes or more.
Further, for example, when producing composite particles having a catalytic action, the concentration of the dispersion obtained by dispersing resin particles (average particle diameter of 10 nm to 50 μm) in the second liquid is 0.01 to 40% by mass. From the viewpoint that the catalyst performance is more excellent, a solution having a metal salt concentration of 0.001 to 4 mol / L is placed in the second liquid in which the resin particles are dispersed, at a liquid feed rate of 0.01 to 1 mL / min for 1 minute or more. The conditions for electrospraying can be exemplified.

The generation of the composite particles can be confirmed by visual observation and element qualitative analysis using an SEM (scanning electron microscope) with an EDS (energy dispersive X-ray spectrometer).
After the production of the composite particles, the excess of the additive can be reduced and the concentration operation can be performed by various separation methods as necessary. For reduction of additives and removal of by-product salts, centrifugation, ultrafiltration, ion exchange resins, membranes, and the like can be used as usual techniques. The composite particle dispersion thus obtained can be diluted or concentrated to a predetermined concentration and can be adjusted according to the intended use. Furthermore, the composite particle dispersion contains a polymer resin dispersant, a pigment, a plasticizer, a stabilizer, an antioxidant, and other additives selected from two or more of these, depending on the purpose. You may do it.

The composite particles are used for conductive particles used for conductive materials such as conductive paste, catalysts for plating treatment, and the like.
For example, a composite particle dispersion in which composite particles in which metal particles are attached to the surface of resin particles is dispersed in the second liquid needs to be desalted and purified, and if necessary, a viscosity adjusted step. For example, the conductive material can be used by a method including a step of changing the dispersion medium. Examples of the method for adjusting the viscosity include a method for diluting or concentrating, a method for adding a thickener, and the like. Examples of the concentration method include a method of distilling off the dispersion medium, a method of removing the solvent by centrifugation or decantation, and the like. Examples of the dispersion medium used for the conductive material include ketones such as diethyl ketone, methyl butyl ketone, dipropyl ketone, and cyclohexanone; ethanol, isopropyl alcohol, n-pentanol, 4-methyl-2-pentanol, and cyclohexanol. Alcohols such as diacetone alcohol; ether alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether; acetic acid-n-butyl, amyl acetate Saturated aliphatic monocarboxylic acid alkyl esters such as ethyl lactate, lactic acid esters such as lactic acid-n-butyl; methyl cellosolve acetate, ethyl cellosolve acetate Over DOO, propylene glycol monomethyl ether acetate, can be exemplified and ether-based esters such as ethyl 3-ethoxypropionate, these can be used alone or in combination of two or more.

  In addition, for example, a composite particle dispersion in which composite particles in which metal particles are attached to the surface of resin particles is dispersed in the second liquid includes a step of desalting and purifying, and a step of changing the dispersion medium if necessary. Thus, a catalyst solution can be obtained and used as a catalyst for plating or the like. As a dispersion medium of the catalyst liquid, for example, water or an organic solvent can be used, and acetone, methyl acetoacetate, ethyl acetoacetate, ethylene glycol diacetate, cyclohexanone, acetylacetone, acetophenone, 2- (1-cyclohexenyl) cyclohexanone, Propylene glycol diacetate, triacetin, diethylene glycol diacetate, dioxane, N-methylpyrrolidone, dimethyl carbonate, dimethyl cellosolve and the like can be used, and these can be used alone or in combination of two or more. When the catalyst solution is used as, for example, a catalyst for plating, the composite particles are supported on the plating substrate by contacting the catalyst solution and the plating substrate. Examples of the contacting method include a method of immersing the plating substrate in a catalyst solution and a method of applying or spraying the composite particle dispersion on the plating substrate. Moreover, after making it contact, you may dry if necessary.

  Although the embodiments of the present invention have been described so far, the present invention is not limited to the above-described embodiments. The present invention can be modified and changed based on the technical idea.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples.
Composite particles were formed by electrostatic spraying using the same apparatus as in FIG.
Formation of the composite particles was confirmed by observation of the composite particles and element qualitative using an SEM (scanning electron microscope) with an EDS (energy dispersive X-ray spectrometer).
Conductivity is to apply the slurry (conductive material) containing the composite particles obtained in the examples to a glass plate, heat-treat at 180 ° C., and measure the electrical resistivity with a digital multimeter R6552 (manufactured by Advantest). It was evaluated by.

Example 1
Dispersion containing polyethylene terephthalate particles (Casesol ES-9 manufactured by Nikka Chemical Co., Ltd., average particle size 0.2 μm) with 100 ml of pure water added with 0.5 g of polyvinylpyrrolidone and 5 g of ascorbic acid in a 200 ml beaker Was dispersed in an amount such that the polyethylene terephthalate particles were 0.1 g. As a low dielectric constant liquid, 100 ml of normal hexane was disposed in the upper layer, an electrode was placed as a positive electrode on a glass capillary nozzle (caliber 50 μm), and a voltage of +2 kV was applied by a power source (high voltage power source HAR manufactured by Matsusada Precision Co., Ltd.). The nozzle is set in the normal hexane phase at a position 1 cm away from the interface of the aqueous phase (W1 = 5 cm, W2 = 1 cm), a stainless steel flat plate is placed at the bottom of the aqueous phase as the negative electrode, 2 kV was applied. While stirring with a magnetic stirrer, the potential difference was 4 kV, and a 1.0 mol / L silver nitrate aqueous solution was electrostatically sprayed at a liquid feed rate of 0.5 ml / min for 60 minutes. After spraying, the aqueous phase was separated from the normal hexane phase to obtain a composite particle dispersion.
The obtained composite particle dispersion was slurried by decantation using a centrifugation operation as follows. Separation was carried out at 10,000 rpm with a micro cooling centrifuge 1700 manufactured by Kubota Corporation, the upper layer aqueous solution was taken out, and the same amount of distilled water was added, followed by further centrifugation operation. This operation was repeated three times, and the lower layer composite particles were collected, made up to 1 ml with distilled water, and treated with a handy homogenizer (manufactured by ASONE) to obtain composite particle-containing slurry.
When the obtained composite particle-containing slurry was dried on aluminum foil and analyzed by SEM-EDS, composite particles having a silver layer formed on the surface of the polyester particles were observed. The silver layer was confirmed by detection of elemental silver from the composite particles, and was composed of silver particles having an average particle diameter of 10 nm and a thickness of 20 nm.
Further, the slurry was applied on a slide glass, and heat treatment was performed for 60 minutes in an atmosphere of 180 ° C. in a hot air blowing type oven dryer. It was 7 * 10 < ^-5 > ohm * cm as a result of measuring an electrical resistivity with R6552 by ADVANTEST company, and a multi digital meter.

Example 2
In a 200 ml beaker, 100 ml of pure water added with 0.5 g of polyvinylpyrrolidone and 0.1 g of ascorbic acid is placed in the lower layer, and 0.1 g of polystyrene particles (Technopolymer SBX-4 produced by Sekisui Plastics Co., Ltd., average particle size 4 μm). Was dispersed. An isoparaffinic solvent, 100 ml of IP solvent IP-1620 (manufactured by Idemitsu Kosan Co., Ltd.) is placed as a low dielectric constant solvent in the upper layer, an electrode is placed on a glass capillary nozzle (50 μm in diameter) as a positive electrode, and a power source (high pressure from Matsusada Precision Co., Ltd. A voltage of +5 kV was applied by the power supply HAR). The nozzle was set in the air at a position 1 cm away from the isoparaffin interface (W1 = 5 cm, W2 = 1 cm), a stainless steel plate was placed at the bottom of the aqueous phase as the negative electrode, and −2 kV was applied by a power source (similar to the positive electrode). . While stirring with a magnetic stirrer, the potential difference was set to 6 kV, spraying was performed at a liquid speed of 0.1 mol / chloroauric acid aqueous solution 0.1 ml / min, and spraying was performed for 60 minutes. After spraying, the aqueous phase was separated from the normal hexane phase to obtain a composite particle dispersion.
Decantation treatment was performed in the same manner as in Example 1 and composite particle formation was confirmed by SEM-EDS. As a result, composite particles in which a gold layer was formed on the polystyrene particle surface were observed, and the gold layer had an average particle diameter of 8 nm. It was composed of gold particles and had a thickness of 10 nm. As a result of evaluating the conductivity in the same manner as in Example 1, a conductivity of 5 × 10 ⁻⁴ Ω · cm was shown.

Example 3
In a 200 ml beaker, 100 ml of pure water added with 0.5 g of polyvinylpyrrolidone and 0.15 g of hydrated hydrazine is placed in the lower layer, and 0.1 g of acrylic particles (Technopolymer AFX-8 manufactured by Sekisui Plastics Co., Ltd., average particle size 8 μm) Was dispersed. As an upper layer low dielectric constant solvent, 50 ml of normal hexane was disposed, and a nozzle was disposed in the same manner as in Example 1. A voltage of +2 kV was applied to the positive electrode, and −2 kV was applied to the negative electrode. While stirring with a magnetic stirrer, the potential difference was set to 4 kV, and a 1 mol / L silver nitrate aqueous solution was sprayed at a liquid speed of 0.1 ml / min, and sprayed for 60 minutes. After spraying, the aqueous phase was separated from the normal hexane phase to obtain a composite particle dispersion.
Decantation treatment was carried out in the same manner as in Example 1 and composite particle formation was confirmed by SEM-EDS. As a result, composite particles in which a silver layer was formed on the surface of the acrylic particles were observed, and the silver layer had an average particle diameter of 10 nm. It was composed of silver particles and had a thickness of 20 nm. As a result of evaluating the conductivity in the same manner as in Example 1, the conductivity was 8 × 10 ⁻⁴ Ω · cm.

Example 4
In a 200 ml beaker, 100 ml of pure water added with 0.5 g of polyvinyl alcohol and 0.15 g of hydrated hydrazine is disposed in the lower layer, and 0.1 g of urethane particles (Pearlsen U-102A manufactured by Tosoh Corporation, average particle size 40 μm) are dispersed. It was. As an upper layer low-dielectric constant solvent, 100 ml of normal hexane was disposed, and a nozzle was disposed in the same manner as in Example 1. A voltage of +2 kV was applied to the positive electrode, and −2 kV was applied to the negative electrode. While stirring with a magnetic stirrer, the potential difference was set to 4 kV, and a 1.0 mol / L silver nitrate aqueous solution was sprayed at a liquid speed of 0.1 ml / min, and sprayed for 60 minutes. After spraying, the aqueous phase was separated from the normal hexane phase to obtain a composite particle dispersion.
Decantation treatment was performed in the same manner as in Example 1 and composite particle formation was confirmed by SEM-EDS. As a result, composite particles in which a silver layer was formed on the urethane particle surface were observed, and the silver layer had an average particle diameter of 12 nm. It was composed of silver particles and had a thickness of 20 nm. As a result of evaluating the conductivity in the same manner as in Example 1, a conductivity of 5 × 10 ⁻⁵ Ω · cm was shown.

Example 5
In a 200 ml beaker, 100 g of pure water to which 0.5 g of polyoxyethylene sorbitan monooleate (product name: Tween 80, manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.1 g of ascorbic acid were added was placed in the lower layer, and urethane particles (Tosoh Corporation) 0.1 g of Parrsen U-102A (average particle diameter 40 μm) was dispersed. As an upper layer low-dielectric constant solvent, 100 ml of normal hexane was disposed, and a nozzle was disposed in the same manner as in Example 1. A voltage of +5 kV was applied to the positive electrode, and −2 kV was applied to the negative electrode. While stirring with a magnetic stirrer, the potential difference was set to 6 kV, and a 0.01 mol / L chloroplatinic acid aqueous solution was sprayed at a liquid speed of 0.01 ml / min, and sprayed for 10 minutes. After spraying, the aqueous phase was separated from the normal hexane phase to obtain a composite particle dispersion.
Decantation treatment was performed in the same manner as in Example 1 to obtain catalyst particles made up to 1 ml. When composite particle formation was confirmed by SEM-EDS, composite particles in which a platinum layer was formed on the surface of the urethane particles were observed. The platinum layer was composed of platinum particles having an average particle diameter of 8 nm and the thickness was 10 nm. .
The dispersion was impregnated into 5A filter paper manufactured by ADVANTEC and dried. To the nickel plating solution adjusted to pH 9 and 40 ° C. with nickel sulfate hexahydrate 90 g / L, sodium citrate dihydrate 10 g / L, ammonium chloride 20 g / L, 25% aqueous ammonia, Soaked for 10 minutes. After washing with water, observation confirmed that a nickel plating film was formed on the filter paper impregnated with the catalyst particles.

Comparative Example 1
In a 100 ml beaker, 0.1 g of acrylic particles (Technopolymer AFX-8 manufactured by Sekisui Plastics Co., Ltd., average particle size: 8 μm) was dispersed in 50 ml of pure water to which 0.1 g of polyvinylpyrrolidone was added. As a nano silver particle dispersion, 10 ml of ALDRICH, Silver, dispersion, particle size of 10 nm was added and stirred for 60 minutes with a magnetic stirrer.
Decantation was carried out in the same manner as in Example 1, and composite particle formation was confirmed by SEM-EDS, but composite particles were not formed. Also not conductive.

Comparative Example 2
In a 200 ml beaker, 100 ml of pure water added with 0.5 g of polyvinylpyrrolidone and 5 g of ascorbic acid was placed in the lower layer. 100 ml of normal hexane was disposed as an upper layer low dielectric constant solvent, an electrode was placed as a positive electrode on a glass capillary nozzle (caliber 50 μm), and a voltage of +2 kV was applied by a power source (high voltage power source HAR manufactured by Matsusada Precision Co., Ltd.). The nozzle is set in a normal hexane phase at a position 1 cm away from the interface of the aqueous phase (W1 = 5 cm, W2 = 1 cm), a stainless steel flat plate is placed at the bottom of the aqueous phase as the negative electrode, and- 2 kV was applied. While stirring with a magnetic stirrer, the potential difference was set to 4 kV, and a 1 mol / L silver nitrate aqueous solution was sprayed at a liquid speed of 0.5 ml / min, and sprayed for 60 minutes to obtain a nanoparticle dispersion. The result of measurement by DLS was 8 nm. In this nanosilver dispersion, a dispersion containing polyethylene terephthalate particles (Casesol ES-9 manufactured by Nikka Chemical Co., Ltd., average particle size 0.2 μm) was dispersed in an amount such that the polyethylene terephthalate particles were 0.5 g. After stirring for 60 minutes with a magnetic stirrer, decantation treatment was performed in the same manner as in Example 1, and composite particle formation was confirmed by SEM-EDS, but composite particles were not formed. Also not conductive.

Table 1 shows the evaluation results of Examples and Comparative Examples.
From the results of Examples, metal-resin composite particles are easily formed by spraying a metal aqueous solution in the form of an electrospray (electrostatic spray) to resin particles dispersed in an aqueous solution, and reducing the metal-resin composite particles. It can be seen that it can be used as a catalyst for a conductive material and plating treatment.

DESCRIPTION OF SYMBOLS 1 Electrospray nozzle 1a Spray port 4 Electrode 5 Power supply 6 Container LL Low dielectric constant liquid L1 1st liquid L2 2nd liquid P1 Low dielectric constant liquid phase P2 2nd liquid phase W1 The distance of the spray port 1a and the electrode 4 W2 Distance between the spray port 1a and the interface between the low dielectric constant liquid phase P1 and the second liquid phase

Claims (3)

  Dissolving the reducing agent, dissolving or dispersing the dispersing agent, and arranging the second liquid phase in which the resin particles are dispersed and the low dielectric constant liquid phase so as to separate into two phases, Is arranged in the phase of the low dielectric constant liquid, or is arranged so as to face the liquid surface of the phase of the low dielectric constant liquid at a position away from the two phases to the phase side of the low dielectric constant liquid, In the state where the electrode is disposed in the phase of the second liquid, the liquid droplet is charged by applying a potential difference between the nozzle and the electrode, and the liquid droplet of the first liquid in which the metal salt is dissolved, The metal salt which is electrostatically sprayed from the spraying port of the nozzle and reaches the second liquid phase through the low dielectric constant liquid phase is subjected to a reduction reaction with the reducing agent, and the generated metal particles are the resin particles. A composite particle dispersion obtained by dispersing composite particles attached to the surface of the liquid in a second liquid is obtained. Tsu comprising at least a flop method for producing a composite particle dispersion.   The method for producing a composite particle dispersion according to claim 1, wherein an average particle diameter of the resin particles before the reduction reaction is 10 nm to 50 μm and is larger than an average particle diameter of the metal particles.   The method for producing a composite particle dispersion according to claim 1 or 2, wherein the concentration of the solution or dispersion obtained by dissolving or dispersing the dispersant in the second liquid is 0.1 mass% to 10 mass%. .

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